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was quite variable ranging from no survival in enclosures stocked at 18,000, 1,200 and <br />8001arvae/acre to 11 °Io survival in an enclosure stocked at 36,000 larvae/acre. Survival <br />of razorback sucker larvae in the enclosure that had a significantly higher composition of <br />black bullhead was 3.95%. This was the third highest estimated survival rate among the <br />twelve enclosures. <br />These survival estimates are conservative, based on the likelihood of escapement <br />from the enclosures of larval razorback sucker. Escapement was evaluated by setting <br />nine fyke nets outside and on the perimeter of the enclosures for three nights in 2003. <br />Nonnative species and one bonytail was all that was captured with this effort. <br />Larval razorback sucker stocked into the experimental enclosures on 20 June <br />2003 had grown to a mean length of 49 mm at the time of sampling. Growth rates <br />averaged 0.6 mm/day for the average of 64 days they were in the enclosures. Growth <br />rates ranged from 0.40mm/day in and enclosure stocked at 18,000 larvae/acre to <br />0.92mm/day in and enclosure stocked at 4,000 larvae/acre. Surviving razorback sucker <br />were transferred to The Stirrup floodplain wetland. <br />Abundance estimates of nonnative species in each enclosure ranged from 3,993 <br />to 15,216 in 2003. Enclosures with higher nonnative fish densities showed comparable <br />survival of razorback sucker as the enclosures containing lower densities of nonnative <br />fish (Table 6; Figure 1). The highest razorback sucker survival was detected in an <br />enclosure with the third highest density of nonnative fish. <br />11 <br />